Introduce PlatformEvent to handle Device events, Battery events and Gamepad events.

Source/core/frame/PlatformEventController.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
-#include "core/frame/DeviceEventControllerBase.h"
+#include "core/frame/PlatformEventController.h"
 
 #include "core/page/Page.h"
 
 namespace blink {
 
-DeviceEventControllerBase::DeviceEventControllerBase(Page* page)
+PlatformEventController::PlatformEventController(Page* page)
     : PageLifecycleObserver(page)
     , m_hasEventListener(false)
     , m_isActive(false)
-    , m_timer(this, &DeviceEventControllerBase::oneShotCallback)
+    , m_timer(this, &PlatformEventController::oneShotCallback)
 {
 }
 
-DeviceEventControllerBase::~DeviceEventControllerBase()
+PlatformEventController::~PlatformEventController()
 {
 }
 
-void DeviceEventControllerBase::oneShotCallback(Timer<DeviceEventControllerBase>* timer)
+void PlatformEventController::oneShotCallback(Timer<PlatformEventController>* timer)
 {
     ASSERT_UNUSED(timer, timer == &m_timer);
     ASSERT(hasLastData());
     ASSERT(!m_timer.isActive());
 
     didUpdateData();
 }
 
-void DeviceEventControllerBase::startUpdating()
+void PlatformEventController::startUpdating()
 {
     if (m_isActive)
         return;
 
     if (hasLastData() && !m_timer.isActive()) {
         // Make sure to fire the data as soon as possible.
         m_timer.startOneShot(0, FROM_HERE);
     }
 
     registerWithDispatcher();
     m_isActive = true;
 }
 
-void DeviceEventControllerBase::stopUpdating()
+void PlatformEventController::stopUpdating()
 {
     if (!m_isActive)
         return;
 
     if (m_timer.isActive())
         m_timer.stop();
 
     unregisterWithDispatcher();
     m_isActive = false;
 }
 
-void DeviceEventControllerBase::pageVisibilityChanged()
+void PlatformEventController::pageVisibilityChanged()
 {
     if (!m_hasEventListener)
         return;
 
     if (page()->visibilityState() == PageVisibilityStateVisible)
         startUpdating();
     else
         stopUpdating();
 }
 
 } // namespace blink